JP2007205250A - Pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump device in which pump efficiency is improved by reducing a clearance in normal operation, variation in relief pressure performing relief of high-pressure fluid in overload is small, and the overload of stable operation is prevented. <P>SOLUTION: A side plate 17 disposed between a rotor 10 and a side housing 6 and fitted to a cam face 12 of a ring housing 4 and supported to be slidable in an axial direction, and an urging means 18 urging the side plate 17 on a rotor side, are provided. A space formed between the side plate 17 and the side housing 6 communicates with an intake port 15a. Therefore, in a normal operating condition, the side plate 17 is pressed against the rotor 10 by an urging force so as to reduce a side clearance of a rotor end face and improve the pump efficiency. In the overload by high-speed revolution of the rotor 10, discharge pressure of high-pressure air pushes back the side plate 17 against the urging force so as to perform stable relief of the high-pressure air on an intake passage side and prevent the overload. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pump device that sucks and discharges fluid by volume fluctuation accompanying rotation of a rotor, and particularly relates to prevention of overload when a discharge pressure of a predetermined value or more acts during high-speed rotation of a rotor. .

[Conventional technology]
2. Description of the Related Art Conventionally, as a pump device, a vane pump in which a rotor with vanes housed in a pump chamber of a housing is rotationally driven to suck fluid and pressurize and discharge is known. For example, in a hydraulic coupling (fluid coupling) device that is a power transmission device of a four-wheel drive vehicle as disclosed in Patent Document 1, a difference in rotational speed between front wheels and rear wheels or a difference in rotational speed between left and right wheels occurs. Vane pumps, which are sometimes used to generate rear wheel drive force by generating fluid coupling functions, have special relief to prevent excessive pressure from being applied to each part of the vane pump due to high discharge pressure due to high speed rotation. Without requiring a valve, a flexible part that deforms with a predetermined discharge pressure is formed on the side plate of the pump chamber that houses the rotor with vanes, and the deformation of the flexible part allows fluid to flow between the side plate and the rotor. A vane pump characterized by forming a gap for leaking has been proposed.

  3A shows a longitudinal sectional view of a vane pump of a conventional hydraulic coupling device, and FIG. 3B shows an enlarged sectional view of a side plate portion of the vane pump. The structure of the hydraulic coupling device H will be briefly described with reference to FIG.

  The hydraulic coupling device H includes a left vane pump PL and a right vane pump PR that are arranged symmetrically. The left and right vane pumps PL and PR are provided with a left first side plate 61L, a left cam ring 62L, a second side plate 63, a right cam ring 62R, and a right first side plate 61R, and are integrally coupled with a plurality of bolts 64 and are thin-walled. A cylindrical casing 65 is fitted.

  The outer end portions of the left and right first side plates 61L and 61R are supported by the housing 73 via the ball bearing 72 in the projecting annular support portion 61a, and the inner peripheral surface of the support portion 61a is left and right via the ball bearing 74. It is supported by the rotor shafts 75L and 75R. A left rotor 77L splined to the left rotor shaft 75L is rotatably housed in a space surrounded by the left first side plate 61L, the left cam ring 62L, and the second side plate 63. Similarly, the right rotor 77R is a right cam ring. Housed in 62R. The left and right cam rings 62L and 62R are rotationally connected to the front wheels by the bevel gear 51, while the rotors 77L and 77R are splined to the rear wheel axles 53L and 53R. Relative rotation is possible.

  Plate-like vanes 92 are slidably supported in a plurality of vane grooves 77a formed radially on the rotors 77L and 77R, and the radially outer ends of the vanes 92 are the inner circumferences of the left and right cam rings 62L and 62R. A spring 93 and a vane push-up port 77b are disposed at the bottom of the vane groove 77a so as to be in sliding contact with the surface and to be in close contact with the inner peripheral surface.

  The second side plate 63 is a component common to the left vane pump PL and the right vane pump PR, and includes a left valve plate 71L and a right valve plate 71R, and is opposed to the left and right rotor shafts 75L and 75R via needle bearings 78, respectively. The part is supported so as to be relatively rotatable. In addition, suction ports 94L and 94R and discharge ports 95L and 95R are provided on the outer surfaces of the left and right valve plates 71L and 71R on the cam ring side, and communication grooves that switch communication with each other via check valves 99 and 98 are formed. An oil passage such as a communication groove is provided on the inner surface (on the opposite cam ring side) of the valve plates 71L and 71R. The suction ports 94L and 94R and the discharge ports 95L and 95R are communicated with each other via an orifice (not shown), and the left and right vane pumps PL and PR are mutually connected with the suction ports 94L and 94R and the discharge ports 95L and 95R. It is configured to communicate through an orifice (not shown).

  Further, as shown in FIG. 3 (b), an annular groove 61c extending radially outward is formed in the vicinity of the inner peripheral portion of the right first side plate 61R facing the right rotor 77R, thereby bending outward in the axial direction. An easily thin flexible portion 61d is formed. A vane push-up port 77b to which a high-pressure fluid is supplied is located in the vicinity of the flexible portion 61d. When the right vane pump PR rotates at a high speed and the discharge pressure exceeds a predetermined pressure, the pressure acting on the vane push-up port 77b. Thus, the flexible portion 61d of the right first side plate 61R is bent and deformed so as to be separated from the right rotor 77R, and a gap is formed there. As a result, the high-pressure fluid in the vane push-up port 77b passes through this gap, and further passes through the spline coupling portion between the right rotor shaft 75R and the right rotor 77R, and is released to the right reservoir 79R.

  The hydraulic coupling device H including the left and right vane pumps PL and PR, for example, in a state where the vehicle is traveling at a constant speed, does not cause a difference in rotational speed between the front and rear wheels, and the rotational speed of the left and right cam rings 62L and 62R and the left and right rotors. The rotational speeds of 77L and 77R coincide with each other so that relative rotation does not occur. As a result, since the left and right vane pumps PL and PR do not discharge the working fluid, the hydraulic coupling device H does not transmit the driving force, and the vehicle is in the front wheel driving state.

  However, if the front wheels slip when starting or suddenly accelerating, the relative rotation in the forward rotation direction is between the left and right cam rings 62L and 62R linked to the rotation of the front wheels and the left and right rotors 77L and 77R linked to the rotation of the rear wheels. The left and right vane pumps PL and PR return the working fluid discharged from the discharge ports 95L and 95R to the suction ports 94L and 94R through the left and right orifices. At this time, a load is generated in the left and right vane pumps PL and PR due to the flow resistance, and this load is transmitted as a driving force to the left and right rear wheels. That is, when the front wheel slips, the four-wheel drive state is set, and the driving force of the vehicle can be increased.

  Also, when the vehicle makes a tight turn at low speed, or when the left and right frictional forces of the wheels are different, for example, when only the right wheel slips in mud, the left and right vane pumps PL, PR cam rings 62L , 62R and the rotors 77L, 77R generate relative rotation. Moreover, the magnitude of relative rotation differs between the left and right vane pumps PL and PR. At this time as well, a load is generated in the left and right vane pumps PL and PR due to the flow resistance of the orifice as described above, and a driving force is generated. That is, the function of a so-called differential limiting mechanism (SLD) can be exhibited.

  When the rotational speed of the front wheels is higher than that of the rear wheels, such as at the time of starting or sudden acceleration described above, the left and right rotors 77L and 77R rotate relative to each other in the forward rotation direction to generate driving force, and conversely, sudden braking When performing the above, the rotors 77L and 77R relatively rotate in the reverse direction. In addition, when the left and right vane pumps PL and PR are rotated at high speed, the flexible portion 61d of the left and right first side plates 61L and 61R is bent to release the high pressure fluid to the low pressure portion (relief). It can be demonstrated. As a result, the relief valve, which has been required in the past, is eliminated to reduce the number of parts and reduce the size and weight, while preventing excessive loads from acting on the left and right vane pumps PL and PR to increase durability. I can do it.

[Problems with conventional technology]
However, in the vane pump as a pump device disclosed in Patent Document 1, the flexible part is often exposed to a high temperature environment, and the variation in the relief pressure due to the large change in the deflection characteristic due to the temperature of the flexible part is large. There is also a problem, and there is a finite but finite gap between the rotor and the side plate, and the pump efficiency decreases because leakage (reflux) occurs from this gap even under normal operating conditions. There is.
JP 2003-278671 A

  Therefore, the present invention has been made in view of the above problems.In normal operation, the clearance is reduced to improve pump efficiency, and in the event of an overload, there is little variation in the relief pressure for relieving high-pressure fluid, and stable operation. An object of the present invention is to provide a pump device capable of preventing overload.

[Means of Claim 1]
In the present invention, there is provided a ring housing having an inner peripheral surface that is smoothly continuous inside, a suction port and a discharge port in a part of the inner peripheral surface, a side housing that sandwiches a side surface of the ring housing, a ring housing, and a side A pump device having a space defined by a housing as a pump chamber, including a rotor rotatably accommodated in the pump chamber, and performing suction and discharge of fluid by volume fluctuation accompanying rotation of the rotor,
A side plate that is disposed between the rotor and the side housing, is fitted to the inner peripheral surface of the ring housing and is slidably supported in the axial direction; and a biasing means that biases the side plate toward the rotor. And a space portion formed between the side plate and the side housing and the suction port are communicated by a suction passage.

  According to this, in a normal operating state, the side plate is pressed against the rotor by the urging force, so that the gap between the rotor end faces becomes as small as possible, leakage from the rotor end faces is reduced, and pump efficiency is improved. When the rotor is overloaded due to high speed rotation, the discharge pressure of the high-pressure fluid acts on the low pressure side via the side plate, and acts to push the side plate back against the urging force. For this reason, the gap between the rotor and the side plate is increased, and the high-pressure fluid is released (relieved) to the low-pressure portion (suction passage side), and overload can be prevented.

[Means of claim 2]
The pump device according to claim 1, wherein the urging means is a spring made of a spring steel material having an urging force corresponding to a predetermined discharge pressure as an offset pressure in advance.

  Thus, the same effect as that of the means of claim 1 can be obtained, but the spring made of spring steel material has a very small change in deformation characteristics due to temperature, so that the variation in relief pressure is small and the operation is stable. In addition, the relief pressure can be set easily and accurately, and can be manufactured at low cost.

The pump device of the best mode according to the first embodiment of the present invention includes a side plate that is disposed between the rotor and the side housing, is fitted on the inner peripheral surface of the ring housing, and is slidably supported in the axial direction. An urging means for urging the side plate toward the rotor side, and a space portion formed between the side plate and the side housing and the suction port are communicated with each other by a suction passage. The side plate is pressed against the rotor to reduce the gap between the rotor end faces to improve the pump efficiency, and the high pressure fluid discharge pressure pushes the side plate against the urging force when the rotor is overloaded. The high-pressure fluid is released to the low-pressure part (suction passage side) (relief), and overload can be prevented.
An embodiment of the present invention will be described together with Example 1 shown in the drawings.

[Configuration of Example 1]
Fig.1 (a) is a longitudinal cross-sectional view of the vane pump in a present Example, FIG.1 (b) is a cross-sectional view in XX of Fig.1 (a).

  The vane pump 1 of the present embodiment corresponds to the pump device of the present invention. For example, a fuel vapor leak inspection module in a vehicle engine canister or an evaporative fuel held in a canister in a state where intake negative pressure is small is taken into an intake pipe. Used to send in. Therefore, the working fluid of the vane pump 1 in the present embodiment is mainly air.

  1A, a vane pump 1 according to this embodiment includes a housing fixed to a vehicle, a rotor 10 rotating in the housing, and a plurality of vanes 2 supported so as to be slidable in the radial direction of the rotor 10. And a side plate structure that closes the side surface of the rotor 10 and an electric motor (drive device) 3 that rotationally drives the rotor 10.

  The housing includes a ring housing 4 that covers the radial direction of the rotor 10 and side housings (first and second side housings 5 and 6) that cover the rotational axis direction of the rotor 10. The ring housing 4 and the first and second side housings 5 and 6 may be separate from each other or may be partially integrated. Specifically, in this embodiment, a housing including a cam housing 9 in which a ring housing 4 and a first side housing 5 are integrally formed and a second side housing 6 is shown. The cam housing 9 and the second side housing 6 are pressed against the motor flange 8 to which the electric motor 3 is fixed by bolts 7 and are fixed in the axial direction.

  The ring housing 4 includes a smoothly continuous cam surface 12 (inner peripheral surface) that is a cylindrical hole shape that is eccentric with respect to the rotating shaft 11 of the electric motor 3. In addition, the rotor 10 has a substantially cylindrical shape, is disposed inside the ring housing 4, and forms a substantially crescent-shaped pump chamber 13 formed by a double circular gap eccentric with the cam surface 12. The rotor 10 is fitted to the rotary shaft 11 of the electric motor 3 by a D-cut or a key groove, and rotates integrally with the rotary shaft 11 of the electric motor 3.

  Further, the rotor 10 is sealed by sliding one side (upper side in the drawing) in contact with the inner surface of the first side housing 5 and sealing the other side (lower side in the drawing) in the side plate structure described later. . Further, as shown in FIG. 1B, the rotor 10 is formed with a plurality of vane grooves 14 that hold the vanes 2 slidably in the radial direction at equal intervals in the circumferential direction.

  The plurality of vanes 2 are plate-like members having a substantially rectangular shape that divide the pump chamber 13 into a plurality of parts, are slidably supported in the plurality of vane grooves 14, and are ejected in a radial direction by centrifugal force due to rotation. Thus, the radially outer edge of the vane 2 is in sliding contact with the cam surface 12. In this way, the vane 2 is rotationally driven by the rotor 10, so that the space volume defined by the vane 2 gradually increases from one end side to the other end side of the pump chamber 13 having a substantially crescent shape. It becomes a structure that decreases after becoming.

  On the other hand, the housing is formed with a suction port 15a that guides air to one end side of the pump chamber 13 (a portion where the increase in spatial volume starts). Similarly, a discharge port 16 a that guides pressurized air to the discharge passage 16 is formed on the other end side of the pump chamber 13 (a portion where the space volume gradually decreases).

  As a result, when the electric motor 3 is energized and the rotating shaft 11 of the electric motor 3 rotates, each space volume defined by the vanes 2 repeats increasing, maximum, and decreasing. As the space volume partitioned by the vane 2 increases, the space volume becomes negative pressure, and air is sucked into the space volume from the suction port 15a. Subsequently, the space volume partitioned by the vanes 2 is reduced, whereby the space volume is pressurized, and the pressurized air is discharged from the discharge port 16a.

  In this embodiment, the pump chamber 13 is formed by an eccentric double-circular crescent-shaped gap. However, the present invention is not limited to this, and the pump chamber 13 is formed by a concentric columnar rotor having an elliptical hole-shaped cam surface. It may be a pump chamber formed. That is, the smooth continuous cam provided with a structure in which the space volume divided by the vanes increases from one end side to the other end side of the pump chamber with respect to the rotation direction of the vanes and then decreases after reaching the maximum. As long as it is a surface

Accordingly, the side plate structure, which is a feature of this embodiment, will be described.
In the vane pump 1, one end side (upstream side of the working fluid flow) of the pump chamber 13 becomes negative pressure, and the other end side (downstream side of the working fluid flow) of the pump chamber 13 is pressurized. For this reason, the recirculation | circulation which the air pressurized from the side clearance formed in the side (axial direction side) of the rotor 10 flows to the negative pressure side will arise. The larger the side clearance is, the more the recirculation is, and even when the folding rotor 10 is pressurized, if the internal recirculation occurs due to the side clearance, it becomes impossible to obtain a sufficient discharge pressure and discharge amount as a pump, and the pump efficiency deteriorates. Will be invited. Therefore, in order to prevent the air pressurized from the side of the rotor 10 from returning to the negative pressure side, the vane pump 1 of the present embodiment employs the following means.

(1) A side which is provided between the side of the rotor 10 and the second side housing 6 and is fitted to the cam surface 12 (inner peripheral surface) of the ring housing 4 and is slidably supported in the axial direction. A plate 17 is provided.
(2) A biasing means 18 for biasing the side plate 17 toward the rotor 10 is provided in the space 19 between the side plate 17 opposite to the rotor and the second side housing 6.
(3) A suction passage 15 is provided that communicates the space 19 between the side plate 17 and the second side housing 6 with the suction port 15a.

  The side plate 17 is a plate-like member that substantially matches the inner peripheral shape of the cam surface 12, and is fitted to the cam surface 12 as described above and supported so as to be slidable in the axial direction. Note that the sliding gap between the side plate 17 and the cam surface 12 is set to be small so as to prevent seal leakage through the sliding gap. The sliding surface with which the side plate 17 abuts against the rotor 10 and the side of the vane 2 is made of a sufficiently smooth metal plate or resin plate, and the end of the rotating shaft 11 of the rotor 10 is substantially at the center. A concave portion is formed that is rotatably inserted.

  The biasing means 18 is a coil spring having a large coil diameter that is compressed between the side plate 17 and the second side housing 6 and presses the side plate 17 toward the rotor 10 by a restoring force. As a result, both sides of the rotor 10 and each vane 2 are assembled with an apparent zero side clearance. Further, since the coil spring which is the urging means 18 is pre-compressed and disposed, the rotor 10 is pressed without being deformed (compressed) until it corresponds to the offset pressure. Note that the coil spring is an example for explaining the embodiment, and other spring structures such as a spring spring made of spring steel or a disc spring may be used as the biasing means until the pressure corresponds to the offset pressure in advance. Any structure can be used as long as it can be elastically (compressed) and arranged.

  The space between the side plate 17 and the second side housing 6 communicates with the suction port 15a. However, the present invention is not limited to this, and may be communicated with the low pressure side, for example, a communication hole communicating with the atmosphere. May be provided independently in the second side housing 6.

[Operation of Example 1]
The operation of the vane pump 1 of the first embodiment will be described below with reference to FIG. When the electric motor 3 is energized and the rotary shaft 11 of the electric motor 3 rotates at a rated speed, the rotor 10 integrated with the rotary shaft 11 rotates. The increase, maximum, and decrease are repeated for each space volume defined by the vane 2. As the space volume partitioned by the vane 2 increases, the space volume becomes negative pressure, and air is sucked into the space volume from the suction port 15a. Subsequently, the space volume partitioned by the vanes 2 is reduced, whereby the space volume is pressurized, and the pressurized air is discharged from the discharge port 16a. At this time, since the side plate 17 is pressed against the rotor 10 by the biasing means 18 such as a coil spring, the side clearance C is rotated by forming a slight gap to hold the lubricating film. Is very rare.

  Further, when the electric motor 3 rotates at a high speed exceeding the rated rotation and the rotor 10 is excessively rotated, the discharge pressure becomes higher in accordance with the above operation, and an excessive load is applied to each part of the vane pump 1. However, since the space on the side opposite to the rotor of the side plate 17 communicates with the suction port 15a, that is, the low pressure side, the biasing means (coil spring) 18 is pushed back (compressed) because the pressure exceeds the offset pressure at a pressure higher than a predetermined discharge pressure. As a result, the side clearance C between the rotor 10 and the side plate 17 is widened, and the high pressure air is relieved to the suction port 15a (low pressure) side. Thereby, it does not pressurize to the discharge pressure more than predetermined discharge pressure.

[Effect of Example 1]
In the present embodiment, a side plate 17 that is disposed between the rotor 10 and the side housing 6, is fitted to the inner peripheral surface of the ring housing 4, and is supported so as to be slidable in the axial direction. A configuration is adopted in which a biasing means 18 biasing to the 10 side is provided, and a space formed between the side plate 17 and the side housing 6 and the suction port 15 a are communicated by the suction passage 15. Accordingly, in a normal operation state, the side plate 17 is pressed against the rotor 10 by the urging force to reduce the side clearance C of the rotor end surface, thereby improving the pump efficiency. This discharge pressure pushes the side plate 17 back to the low pressure side against the urging force, increases the side clearance C, and relieves the high pressure fluid to the low pressure portion (suction passage side), thereby preventing overload.

  At this time, since the biasing means 18 uses a coil spring or the like made of spring steel having an offset pressure corresponding to a predetermined discharge pressure in advance, the change in spring deformation characteristics due to the temperature of the coil spring or the like is very small, and the relief The pressure variation can be reduced, and the operation is stabilized. In addition, the relief pressure can be set easily and accurately, and can be manufactured at low cost.

[Modification]
In the first embodiment, an example in which the present invention is applied to a fuel vapor leak inspection module in a canister or a vane pump 1 used to send evaporated fuel held in a canister to a suction pipe when intake negative pressure is low is shown. However, the present invention may be applied to a vane pump used for other purposes.

  In the first embodiment, the present invention is applied to the vane pump 1 that sucks and discharges air. However, the present invention is applied to a vane pump that sucks and discharges gas (gas, etc.) other than air and a vane pump that pumps liquid. The invention may be applied.

  Further, in the first embodiment, the side plate structure is applied to the vane pump 1, but this is applied to a rotor rotary pump device (for example, a trochoid) that sucks and discharges fluid by volume fluctuation accompanying the rotation of the rotor in the housing. The present invention may be applied to all pumps, scroll pumps, and the like.

(A) is a longitudinal cross-sectional view of a vane pump, (b) is a cross-sectional view in XX of Fig.1 (a) (Example 1). It is a longitudinal cross-sectional view of a vane pump, and is a schematic diagram which shows the flow of the air which is a working fluid (Example 1). (A) is a longitudinal cross-sectional view of the vane pump of a hydraulic coupling apparatus, (b) is an expanded sectional view of the side plate part of a vane pump (conventional example).

Explanation of symbols

1 Vane pump (pump device)
2 Vane 3 Electric motor 4 Ring housing 5 First side housing 6 Second side housing 8 Motor flange 9 Cam housing 10 Rotor 11 Rotating shaft 12 Cam surface (inner peripheral surface of ring housing)
13 Pump chamber 14 Vane groove 15 Suction passage 15a Suction port 16 Discharge passage 16a Discharge port 17 Side plate 18 Biasing means (coil spring)
19 Space

Claims (2)

A ring housing having a smoothly continuous inner peripheral surface and having a suction port and a discharge port in a part of the inner peripheral surface; a side housing sandwiching a side surface of the ring housing; the ring housing and the side A pump device having a space defined by a housing as a pump chamber, including a rotor rotatably accommodated in the pump chamber, and performing suction and discharge of fluid by volume fluctuation accompanying rotation of the rotor,
A side plate that is disposed between the rotor and the side housing, is fitted to the inner peripheral surface of the ring housing and is slidably supported in the axial direction;
A biasing means for biasing the side plate toward the rotor;
A pump device comprising a space formed between the side plate and the side housing and the suction port communicated by a suction passage. The pump device according to claim 1,
The pump device according to claim 1, wherein the biasing means is a spring made of spring steel having an biasing force corresponding to a predetermined discharge pressure as an offset pressure.

Images